The main objective of this study is to determine the mechanism(s) of action of gaseous anesthetics. By using molluscan giant neurons as a model of the more complex vertebrate central nervous system it is possible to study specific neural processes in isolation one from the other, namely, endogenous membrane currents, direct synaptic linkages and membrane receptors to putative transmitters. This project examines the predictions of two general hypotheses of anesthetic action in an attempt to determine: 1. if anesthesia results from a disruption of specific membrane components and the functions they control, and 2. if pressure reversal occurs at the same site as the anesthetic effect. The predictions are that discrete membrane functions will show differing sensitivities and be affected at differing rates from each other and that pressure reversal will show a selective effect on the specific functions.